Sample Dissolution
The rapid dissolution of textile matrices using strong acids and microwave energy prepares samples for elemental analysis. For heavy metal testing, microwave acid digestion breaks down synthetic and natural fibres in closed vessels. This process ensures that the metals are completely dissolved in the acid solution.
The resulting liquid is analyzed for restricted substances like lead or cadmium.
High Pressure
The digestion occurs in sealed fluoropolymer vessels where temperatures and pressures rise far above atmospheric levels. This high-pressure environment allows the acid mixture, usually nitric acid and hydrogen peroxide, to rapidly decompose the tough polyester or cotton fibres. Utilizing microwave acid digestion reduces the preparation time from hours to minutes.
It also prevents the loss of volatile elements during heating, which improves the accuracy of the heavy metal test.
Safety Protocol
Operating microwave digestion systems requires automated pressure and temperature monitoring to prevent vessel ruptures. Modern instruments feature relief valves that release excess gas safely if a reaction proceeds too rapidly. Technicians must wear protective equipment when handling the concentrated acid mixtures.
Proper cooling of the vessels is necessary before opening them.
Analytical Input
The clear, digested solution is diluted with deionized water before injection into analytical instruments. This step is essential for accurate trace metal detection.
